docs: def _get_recording(self, index):
          """Return the recording that contains a given index."""
          assert index >= 0
          recs = np.nonzero((index - self.offsets[:-1]) >= 0)[0]
          if len(recs) == 0:  # pragma: no cover
              # If the index is greater than the total size,
              # return the last recording.
              return len(self.arrs) - 1
          # Return the last recording such that the index is greater than
          # its offset.
          return recs[-1]